Vintage Calculators

[peter scott]

RPN is the only sensible way with calculators. Nobody needs to remain lumbered by the four function and equals rubbish. Use https://thomasokken.com/free42/

Peter

[ppppenguin]

Peter, that looks rather nice. Thank you.

[Mike Watterson]

RPN is the only sensible way with calculators. Nobody needs to remain lumbered by the four function and equals rubbish. Use https://thomasokken.com/free42/

I did have a simple RPN calculator on my phone, now added the free42. Looks good. Thanks.
My wife had an HP RPN calculator.
About 5 years later I had a Jupiter Ace, which uses Forth, a RPN programming language.

[BusyBee]

Reverse polish is a great way to use a calculator.

I can only vaguely remember trying to use this on a calculator, years ago, but you do remind me of programming in 'Forth', which I have done in the past. Not being in industry I have not come across the language for some time. Does anyone know if it is still well used?

Tracy

[television1936]

I unfortunately in the early 1970s bought a Sinclair Scientific calculator. The most awkward thing was it used reverse Polish logic to perform calculations. I seem to remember the calculator did not have a equals button or a floating decimal point.
So say 3456 X1234 had to be entered 3.456E3+1.234E3X which then gave you 4.264704E6. I later found out that the sine cosine functions gave errors of up to 30%.

[ppppenguin]

From what I remember, the Sinclair Scientific had a half broken implementation of RPN.

[television1936]

I know I failed my HNC maths exam using that Sinclair calculator. In those days fail one subject and you had to resit the three other subjects as well, regardless of the fact you had passed them!

[Craig]

When I did my electronics degree from '74 to '77 we were not allowed to use a calculator in exams until the final year. That was really because it was only then that a significant number of students actually had a calculator. So it was log tables, and techniques that are best forgotten. Like filter synthesis by doing long division of complex polynomials in an exam.

It was only post degree that I bought an HP34C. That came into its own because it had numerical integration and solving for roots of a function, which saved my bacon when the only other option was punch cards on the University mainframe.

Going back to Sinclair for a moment, one of the guys bought a QL ("Quantum Leap"). Like any new toy he put in a test programme that he could check the result with a calculator. The result was tantalizingly different. Turned out that common constants were blown into ROM (like e, pi etc). One of those was root(2), and whoever filled in the ROM data put a slightly incorrect number. If you put in root(2.0001) the machine used an algorithm to calculate the result, and got it right. AFAIK Sinclair never owned up to that or corrected it.

[Craig]

From what I remember, the Sinclair Scientific had a half broken implementation of RPN.

It was typical of Sinclair products. Everything was rushed to market and had flakyness, to the extent that in some cases they were launched with people placing orders, months before shipments started. I mentioned the QL. When that eventually arrived it has a casework extension at the back, because the casework was designed before the boards were completed. So they had to put a wart on the back to accommodate the circuit.

The Scientific still needed you to be a log table and slide rule jockey too. I was really hot with that. Still have my Thornton slide rule, but I must have consigned the 7-figure tables to the bin at some point. 4-figure tables - pah! 7 figures for me.

[roadster]

My first calculator was the Sinclair scientific, I still have it somewhere and it was working when last used. I may dig it out and try some error tests. I was good with a slide rule and still use one occasionally just to keep my hand in as I am from the last generation to have used one in anger. My favourite, to use, is still my Thornton AD150, I do like the double sided Thornton A010 but I haven't used it enough to be proficient. I moved onto a Casio FX501P from the Sinclair whilst my brother went the HP route.
I did like RPN.